Adaptive Reactive Power and Voltage Balance System and Method for Substations

Abstract

The present invention discloses an adaptive reactive power voltage balance system and method for a substation. By designing the adaptive reactive power voltage balance system, the original control strategy of global control at the dispatching end is changed. A reactive power voltage balance system is configured in each substation to achieve precise and continuous reactive power voltage control, adapt to voltage regulation in various grid operation modes, and ultimately achieve the balance requirements within the station and the global interest rate balance. This application changes the traditional mode of unified control of reactive power interest rate regulation by the dispatching end and realizes the function of automatically adjusting the reactive power interest rate locally for each bus of each substation. Through the setting of a stepped reactive power compensator, the function of continuously adjustable reactive power capacity is realized. In the case of series power supply of the bus through the distribution network line, small-capacity adjustment can be carried out without causing over-voltage tripping, ensuring the reactive power voltage balance under special operation modes.

Description

Technical Field

[0001] The present invention belongs to the technical field of substation reactive voltage balance, and particularly relates to an adaptive substation reactive voltage balance system and method. Background Art

[0002] Currently, the grid reactive voltage optimization control system (referred to as the AVC system) for grid regulation and control is based on grid automation technology. It calculates the switching of system capacitors and tap adjustments by collecting signals and telemetry values of each substation through the existing D5000 system for monitoring in the dispatching center, and controls relevant equipment through the D5000 system to complete operations, so as to achieve the control of reactive voltage equipment and ensure the automatic control of voltage and reactive power.

[0003] In the prior art, when the grid reactive voltage optimization control system is actually operating, in the initial stage of construction, it is configured based on capacitors with fixed capacities, resulting in the inability to continuously adjust the reactive power capacity of the substation. In the case of main transformer outage, it will face the situation where voltage over-limit or capacitor over-voltage tripping cannot be adjusted. At the same time, in order to ensure the interest rate of 220 kV substations, the reactive voltage balance of this substation will be affected by the interest rate and unable to operate, resulting in unqualified reactive power or voltage of this substation. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems raised in the above background art. By designing an adaptive substation reactive voltage balance system and method, it changes the original control strategy of global control at the dispatching end, configures a reactive voltage balance system in each substation, realizes precise and continuous reactive voltage control, and finally achieves the balance requirements within this substation.

[0005] To achieve the object of the present invention, the present invention discloses an adaptive substation reactive power and voltage balance system, which is characterized in that a stepped reactive power compensator is configured according to the bus to achieve continuous control of the reactive power input capacity; the stepped reactive power compensator includes an SVG reactive power regulating device, a first compensating capacitor, a second compensating capacitor, and a control switch; the SVG reactive power regulating device, the first compensating capacitor, and the second compensating capacitor are respectively connected in parallel to the grid bus through the control switch; the SVG reactive power regulating device is used to achieve continuous regulation of reactive power, and is configured with an SVG control cabinet for controlling the SVG reactive power regulating device according to the instruction to achieve the reactive power capacity required by the instruction; the control switch is a substation capacitor switch, configured with a protection and measurement and control device, which can achieve monitoring of the circuit breaker status and remote control; an adjustment software is set in the substation background machine, and the substation background machine is used to achieve the functions of remote measurement, remote signaling, remote control, and remote adjustment (SCADA) of all station equipment; the adjustment software calculates by reading the remote signaling, remote measurement, and topological relationship information in the substation background machine, and controls the SVG control cabinet and the protection and measurement and control device of the compensating capacitor through the remote control function.

[0006] Further, the substation background machine sends the adjustment capacity size to the SVG control cabinet through the network switch.

[0007] Further, the substation background machine sends a switch opening and closing command to the protection and measurement and control device of the control switch through the network switch to control the switching on and off of the capacitor.

[0008] To achieve the object of the present invention, the present invention also discloses an adaptive substation reactive power and voltage balance method, including the following steps:

[0009] Step 1: Determine the subordination relationship between the stepped reactive power compensator and the bus;

[0010] Step 2: Determine the bus power switch;

[0011] Step 3: Calculate the reactive power difference of the adjusted power switch;

[0012] Step 4: Adjust the bus voltage to keep it within the specified range;

[0013] Step 5: Adjust the interest rate of the 220 kV substation to keep it within the specified range.

[0014] Further, in step 1, the subordination relationship of each set of stepped reactive power compensators is the bus where they are located, and the adjustment software can read it through the topological relationship of the substation background machine; the stepped reactive power compensator is only responsible for adjusting the reactive power and voltage of the bus with a subordination relationship; the subordination relationship between the stepped reactive power compensator and the bus is only related to the primary wiring and has nothing to do with the operation mode.

[0015] Further, in step 2, after determining the affiliated busbar, it is necessary to determine the power switch of the busbar. According to different operating modes of the busbar, the power switches are also different. The operating modes of the busbar can be divided into three types: main transformer power supply operation, bus coupler switch power supply operation, and distribution network line series power supply operation. For the above three situations, the adjustment software first determines the positions of the main transformer switch and the bus coupler switch of the busbar, determines whether it is for the power supply of this substation. If it is not for the power supply of this substation, it is determined as the distribution network line series power supply.

[0016] Further, step 2 specifically includes the following steps:

[0017] Step 2-1: Determine and read the bus coupler switch and the main transformer switch. If one of the positions is in the closed position, it is judged as the power supply of this substation;

[0018] Step 2-2: If the main transformer switch is in the closed position and the bus coupler switch is in the open position, it is the main transformer power supply operation; in the main transformer power supply operation mode, it is necessary to calculate the eligibility of the apparent power in a loop: all the apparent power flowing through the main transformer switch is equal to the sum of the powers of other switches on the busbar. For a busbar, there is

[0019] P 主变 +jQ 主变 =∑P 其他 +jQ 其他

[0020] In the formula, P is the active power, Q is the reactive power, and j is the imaginary number in the apparent power calculation formula;

[0021] When the verification is qualified, the result of the power switch is the main transformer switch; if the verification is unqualified, the adjustment function of this busbar is blocked, and an alarm signal is sent, and the program enters the switch position reading mode again;

[0022] Step 2-3: If the main transformer switch is in the open position and the bus coupler switch is in the closed position, it is the bus coupler switch power supply operation; in the bus coupler switch power supply operation mode, it is necessary to calculate the eligibility of the apparent power in a loop: all the apparent power flowing through the bus coupler switch is equal to the sum of the powers of other switches on the busbar. For a busbar, there is

[0023] P 母联 +jQ 母联 =∑P 其他 +jQ 其他

[0024] When the verification is qualified, the result of the power switch is the bus coupler switch; if the verification is unqualified, the adjustment function of this busbar is blocked, and an alarm signal is sent, and the program enters the switch position reading mode again;

[0025] Step 2-4: If the main transformer switch is in the closed position, the bus tie switch is also in the closed position to supply power to the bus tie switch. In the bus tie switch power supply operation mode, it is necessary to cyclically calculate the eligibility of the apparent power: the apparent power flowing through the main transformer switch is equal to the sum of the power of other switches on the bus plus the apparent power flowing through the bus tie switch. For a bus,

[0026] P 主变 +jQ 主变 =P 母联 +jQ 母联 +∑P 其他 +jQ 其他

[0027] If the verification is qualified, the result of the power switch is the main transformer switch minus the bus tie switch; if the verification is unqualified, the adjustment function of the busbar is locked, and an alarm signal is issued, and the program enters the switch position reading mode again;

[0028] Step 2-5: If it is determined that the distribution network line is in series supply mode, the program calculates the apparent power for each line with the switch in the closed position; for each line n with the switch in the closed position, calculate

[0029] P Ln +jQ Ln =∑P Li +jQ Li

[0030] Where L represents the line, Li represents all lines on the bus except line n; when the equation is established, line n is the power switch of the bus series supply, and the output result is;

[0031] Step 2-6: For the blocking situation, perform a cyclic calculation on the above formula, and release the blocking when the calculation is qualified (the apparent power verification failure will only occur at the moment of the loop closing operation, generally not exceeding 10 minutes, and will be released soon after a new round of position reading); at the same time, for the single-phase grounding abnormality, set the real-time monitoring telesignal signal to automatically block, and automatically unlock when the signal disappears.

[0032] Further, in step 3, for the power supply mode of this substation, before reactive power regulation, the allowable error value of reactive power is determined; that is, how much reactive power is allowed for the power switch, assuming that the allowable reactive power error value is 0.1mvar, then when the reactive power of the power switch Q≤0.1mvar, the regulation function will not be triggered; when the reactive power of the power switch is greater than the reactive power error value (Q>0.1mvar) trigger condition, the difference calculation is performed, and an adjustment instruction is issued to the stepped reactive power compensator to reduce the reactive power value of the power switch to 0;

[0033] When the system is running, it first reads the power switch number and reactive power magnitude of the busbar, and compares the read reactive power value with the allowable reactive power error value. If the reactive power value ≤ the allowable reactive power error value, no adjustment is required; if the reactive power value > the allowable reactive power error value, the current reactive power capacity is analyzed, and an adjustment instruction is sent to the stepped reactive power compensator 1 to issue an adjustment instruction to reduce the reactive power value of the power switch to 0.

[0034] For the series power supply operation mode of the distribution network line, in the special operation mode where the busbar is in series power supply operation through the distribution network line (capacitors cannot be switched on first. To prevent tripping, capacitors should be cut off first, and SVG is used for compensation first. If SVG reaches its maximum value and still cannot compensate, then capacitors are switched on), the relationship between the magnitude of the capacitor input and the voltage change is uncertain. The adjustment of the capacity needs to be determined according to the busbar voltage situation. When the voltage is lower than the rated value, the capacitor input is increased; when the voltage is higher than the rated value, the capacitor input is decreased. To prevent excessive capacitor input from causing tripping, the increase and decrease of the capacitor input shall not be greater than 0.05 mvar / min.

[0035] Furthermore, in step 4, voltage regulation is only applicable to the power supply mode of this substation (for non-this power supply station, manual regulation is generally not applicable). After determining the allowable reactive power error value (assuming the allowable reactive power error value is 0.1 mvar), after detection, when the reactive power value Q of the power switch ≤ the allowable reactive power error value (0.1 mvar), if the busbar voltage does not meet the voltage qualification requirements, the main transformer tap will participate in voltage regulation, and the tap will be raised or lowered according to the actual situation to meet the voltage qualification requirements.

[0036] The tap only participates in voltage regulation when the reactive power value Q of the power switch ≤ 0.1 mvar. If the reactive power value Q > 0.1 mvar, the tap will participate in voltage regulation only after reactive power regulation is completed and the reactive power value Q ≤ 0.1 mvar.

[0037] Furthermore, to prevent the 220 kV busbar interest rate from still not meeting the interest rate requirements after the reactive power and voltage balance adjustments of this station and the lower-level substations, stepped reactive power compensators are installed on the low-voltage side of the 220 kV substation. On the premise of ensuring qualified voltage, all the stepped reactive power compensators on this busbar are only used to adjust the reactive power required for the interest rate. After the interest rate becomes unqualified, wait for 5 minutes to give the lower-level substations sufficient action time. If the interest rate requirements are still not met after 5 minutes, the adjustment software reads the reactive power value required for calculating the overall power factor in the substation background computer and inputs the corresponding reactive power to meet the interest rate requirements.

[0038] Compared with the prior art, the significant progress of the present invention lies in: 1) It changes the traditional mode of unified control of reactive power rate regulation by the dispatching end, and realizes the function of automatically regulating the reactive power rate locally for each bus of each substation; 2) By setting the stepped reactive power compensator, the function of continuously adjustable reactive power capacity is realized. In the case of the bus running in series through the distribution network line, small-capacity adjustment can be carried out without causing overvoltage tripping, ensuring the reactive power voltage balance under special operating modes; 3) For each bus, its power supply switch can be dynamically captured, and the reactive power value of the power supply switch is used to control the power; 4) The adjustment of the rate is carried out in a way that the lower-level substation first satisfies its own reactive power voltage balance and then satisfies the rate balance, with an upward adjustment from bottom to top.

[0039] To more clearly illustrate the functional characteristics and structural parameters of the present invention, the following further explains in conjunction with the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings described herein are used to provide a further understanding of the present invention, form a part of this application, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings:

[0041] Figure 1 is a schematic diagram of the stepped reactive power compensation equipment;

[0042] Figure 2 is a schematic diagram of the reactive power control and regulation network;

[0043] Figure 3 is the implementation method of automatic balance of reactive power rate;

[0044] Figure 4 is a schematic diagram of the main transformer power supply operation;

[0045] Figure 5 is a schematic diagram of the bus tie switch power supply operation;

[0046] Figure 6 is a schematic diagram of the distribution network line series power supply operation;

[0047] Figure 7 is a schematic diagram of the power supply switch determination process;

[0048] Figure 8 is a schematic diagram of the reactive power regulation process of the power supply of this substation;

[0049] Figure 9 is a schematic diagram of the rate regulation of a 220 kV substation;

[0050] The reference numerals in the figure are: step-type reactive power compensator 1, SVG reactive power regulating device 2, first compensation capacitor 3, second compensation capacitor 4, substation background machine 5, SVG control cabinet 6, C1 measurement and control device 7, C2 measurement and control device 8, control switch 9, and regulation software 10. Detailed implementation manners

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] As Figure 1 shown, the present invention realizes continuous control of the reactive power input capacity by configuring a step-type reactive power compensator 1 according to the bus. The step-type reactive power compensator 1 consists of an SVG reactive power regulating device 2, a first compensation capacitor 3, a second compensation capacitor 4, and a control switch 9. The capacities of the SVG and the capacitors can be freely selected to meet continuous reactive power regulation. For example: when the system capacity is N mvar according to the design requirements, the regulation capacity of the SVG reactive power regulating device 2 ranges from -1 / 4 N mvar to 1 / 4 N mvar, the capacity of the first compensation capacitor 3 is set to 1 / 4 N mvar, and the capacity of the second compensation capacitor 4 is set to 1 / 2 N mvar. Thus, through the switching and regulation of each software content, the step-type reactive power compensator 1 can achieve continuous capacity regulation from -1 / 4 N mvar to N mvar.

[0053] As Figure 2 shown, the substation background machine 5 sends the regulation capacity size to the SVG control cabinet 6 through a network switch; and sends switch opening and closing commands to the protection measurement and control devices (C1 measurement and control device 7, C2 measurement and control device 8) of the control switch 9 to control the switching of the capacitors.

[0054] As Figure 3 shown, the implementation method of the adaptive substation reactive power and voltage balance system is to first ensure the reactive power and voltage balance of each substation, and finally ensure the interest rate balance of the 220 kV substation. During actual operation, when the reactive power capacity of the power grid reaches balance, the regulation of the substation reactive power Q voltage and the regulation of the interest rate (active power P / apparent power S) are actually synchronous. During the regulation process of the reactive power and voltage balance of the substation, the reactive power and voltage balance regulation should be carried out first, and then the voltage regulation.

[0055] As Figure 4 、 5, as shown in Figure 6, affiliation determination (determine which busbar, establish the affiliation between the busbar and the compensation device, and inform the software): The affiliation of each set of step-type reactive power compensator 1 is the busbar where it is located, and the adjustment software can read it through the topological relationship of the substation background machine 5; The step-type reactive power compensator 1 is only responsible for adjusting the reactive power and voltage of the busbar with an affiliation relationship, greatly optimizing the calculation strategy. The affiliation relationship is only related to the primary wiring and has nothing to do with the operation mode. For example Figure 4 , Figure 5 , Figure 6 For the three operation modes shown, the step-type reactive power compensator 1 belongs to Bus 1.

[0056] For example Figure 7 as shown, power switch determination (find the power source): After determining the affiliated busbar, it is necessary to determine the power switch of the busbar. According to different operation modes of the busbar, the power switch is also different. The operation modes of the busbar can be divided into three types: main transformer power supply operation ( Figure 4 ), bus coupler switch power supply operation ( Figure 5 ), and distribution network line series power supply operation ( Figure 6 ). For the above three situations, the adjustment software first determines the positions of the main transformer switches (101, 102) and the bus coupler switch (110) of the busbar to determine whether it is powered by this substation. If it is not powered by this substation, it is determined as distribution network line series power supply.

[0057] First, determine whether to read the bus coupler switch and the main transformer switch. If one of the positions is in the closed position, it is determined that the power supply is from this substation.

[0058] If the main transformer switch is in the closed position and the bus coupler switch is in the open position, it is the main transformer power supply operation. In the main transformer power supply operation mode, it is necessary to cycle and calculate the compliance of the apparent power: The apparent power flowing through all the main transformer switches is equal to the sum of the powers of other switches on the busbar. For Bus 1, there is: P1 + jQ1 = ∑P i + jQ i (in the formula, P is active power and Q is reactive power), and i represents each of the other switches on Bus 1; For Bus 2, there is: P2 + jQ2 = ∑P i + jQ i , and i represents each of the other switches on Bus 2. When the verification is qualified, the result of the power switch is the main transformer switch: Switch 101. If the verification is unqualified, the adjustment function of this busbar is blocked, and an alarm signal is issued. The program enters the switch position reading mode again. The unlocking method is through qualified cyclic power calculation.

[0059] If the main transformer switch is in the open position and the bus coupler switch is in the closed position, it is the bus coupler switch power supply operation (corresponding to Figure 5 Bus 1 in the figure), and in the bus coupler switch power supply operation mode, it is necessary to cycle and calculate the compliance of the apparent power: The apparent power flowing through all the bus coupler switches is equal to the sum of the powers of other switches on the busbar. For Bus 1, there is:

[0060] P3 + jQ3 = ∑P i + jQ i (In the formula, P is active power and Q is reactive power), i represents each of the other switches on Bus 1. When the check is qualified, the result of the power supply switch is the bus tie switch: Switch 110. If the check is unqualified, the regulation function of this bus is blocked, and an alarm signal is sent. The program then enters the switch position reading mode again. The unlocking method is through qualified cyclic power calculation.

[0061] If the main transformer switch is in the closed position and the bus tie switch is also in the closed position, it also supplies power to the bus tie switch (corresponding to Figure 5 Bus 2 in). In the power supply operation mode of the bus tie switch, it is necessary to cyclically calculate the qualification of the apparent power: The apparent power flowing through all the main transformer switches is equal to the sum of the powers of the other switches on the bus + the apparent power flowing through the bus tie switch. For Bus 2, there is: P2 + jQ2 = P3 + jQ3 + ∑P i + jQ i (In the formula, P is active power and Q is reactive power), i represents each of the other switches on Bus 2. When the check is qualified, the result of the power supply switch is the main transformer switch - bus tie switch: Switch 102 - 110. If the check is unqualified, the regulation function of this bus is blocked, and an alarm signal is sent. The program then enters the switch position reading mode again. The unlocking method is through qualified cyclic power calculation.

[0062] If it is determined to be the parallel power supply operation mode of the distribution network line (corresponding to Figure 6 ), the program calculates the apparent power for each line with the switch in the closed position. For each line n with the switch in the closed position, calculate PLn + jQLn = ∑P Li + jQ Li (In the formula, P is active power and Q is reactive power), Li represents the apparent power of each of the other switches in the closed position on Bus 1 except for line n. When the equation holds, line n is the power supply switch for the parallel power supply of this bus, and the result is output.

[0063] For the blocked situation, the situation where the cyclic apparent power check is unqualified only occurs at the moment of closing the loop, generally not exceeding 10 minutes, and will soon be unlocked through a new round of position reading. At the same time, for the single - phase grounding abnormal situation, a real - time monitoring telemetry signal is set for automatic blocking, and automatic unlocking occurs when the signal disappears.

[0064] Such as Figure 8As shown in the figure, the reactive power difference calculation and regulation for the power supply mode of this substation are as follows: Before reactive power regulation, determine the allowable error value of reactive power, that is, how much reactive power the power switch is allowed to have. Assume that the allowable reactive power error value is 0.1 mvar. Then, when the reactive power Q of the power switch ≤ 0.1 mvar, the regulation function will not be triggered. When Q > 0.1 mvar meets the trigger condition, the difference calculation is performed, and a regulation instruction is sent to the stepped reactive power compensator 1 to reduce the reactive power value of the power switch to 0. When the system is running, first read the power switch number and reactive power magnitude of this bus, and compare the read reactive power value with the allowable reactive power error value. If the reactive power value ≤ the allowable reactive power error value, no regulation is required; if the reactive power value > the allowable reactive power error value, analyze the current reactive power capacity, send a regulation instruction to the stepped reactive power compensator 1 to issue a regulation instruction to reduce the reactive power value of the power switch to 0.

[0065] For the series power supply operation mode of the distribution network line: In the special operation mode where the bus is in series power supply operation through the distribution network line (capacitors cannot be switched on first. To prevent tripping, capacitors should be cut off first, and SVG is used for compensation first. If SVG reaches the maximum value and still cannot compensate, then capacitors are switched on), the relationship between the amount of capacitor input and the voltage change is uncertain. The capacity regulation needs to be determined according to the bus voltage situation. When the voltage is lower than the rated value, increase the capacitor input; when the voltage is higher than the rated value, reduce the capacitor input. To prevent excessive capacitor input from causing tripping, the increase and decrease of capacitor input shall not be greater than 0.05 mvar / min.

[0066] Voltage regulation is only applicable to the power supply mode of this substation (for non-this power supply station, manual regulation, which generally does not occur). After determining the allowable error value of reactive power (assuming the allowable reactive power error value is 0.1 mvar), after detection, when the reactive power value Q of the power switch ≤ 0.1 mvar, if the bus voltage does not meet the voltage qualification requirements, the main transformer tap will participate in voltage regulation, and the tap will be raised or lowered according to the actual situation to meet the voltage qualification requirements. Only when the reactive power value Q of the power switch ≤ 0.1 mvar will the tap participate in voltage regulation. If the reactive power value Q > 0.1 mvar, then after reactive power regulation is completed and the reactive power value Q ≤ 0.1 mvar is satisfied, the tap will participate in voltage regulation.

[0067] As Figure 9 shown, for a 220 kV substation, after meeting the reactive power and voltage balance regulation of this station and the lower-level substations, the interest rates gathered at the 220 kV bus basically meet the specified requirements. As Figure 8As shown, in a 220 kV substation with medium-voltage and low-voltage buses on the load side, the reactive power of the medium-voltage side from Station 1 to Station N and the low-voltage side from Station 1 to Station M can all meet the requirement that the reactive power of each substation bus is less than 0.1 mvar (assuming the allowable reactive power error value is 0.1 mvar). If the medium- and low-voltage sides of the 220 kV substation supply power to 10 substations in total, and each substation has 2 load buses, then the reactive power collected on the 220 kV bus side will not exceed 2 mvar, which is sufficient to meet the interest rate requirement.

[0068] To prevent the interest rate from being unqualified due to special circumstances, a stepped reactive power compensator 1 is set on the low-voltage side of the 220 kV substation. On the premise of ensuring qualified voltage, all the stepped reactive power compensators 1 on this bus are only used to adjust the reactive power required for the interest rate. After the interest rate becomes unqualified, wait for 5 minutes to give sufficient action time to the lower-level substations. If the interest rate requirement is still not met after 5 minutes, the adjustment software reads the reactive power value required for calculating the overall power factor in the substation background machine 5 and inputs the corresponding reactive power to meet the interest rate requirement.

[0069] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0070] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An adaptive reactive power and voltage balance method for substations, characterized in that, the system adopted by the method is configured with step-type reactive power compensators (1) according to busbars to achieve continuous control of the reactive power input capacity; the step-type reactive power compensators (1) include SVG reactive power regulation equipment (2), a first compensating capacitor (3), a second compensating capacitor (4), and a control switch (9); the SVG reactive power regulation equipment (2), the first compensating capacitor (3), and the second compensating capacitor (4) are respectively connected in parallel to the grid busbar through the control switch (9); the SVG reactive power regulation equipment (2) is used to achieve continuous regulation of reactive power and is configured with an SVG control cabinet (6) to control the SVG reactive power regulation equipment (2) according to instructions to achieve the reactive power capacity required by the instructions; the control switch (9) is a substation capacitor switch and is configured with a protection and measurement and control device, which can realize the monitoring of the circuit breaker status and remote control; an adjustment software is set in the substation background machine (5), and the substation background machine (5) is used to achieve the functions of remote measurement, remote signaling, remote control, and remote adjustment of all station equipment; the adjustment software calculates by reading the remote signaling, remote measurement, and topological relationship information in the substation background machine (5), and realizes the control of the SVG control cabinet (6) and the protection and measurement and control device of the compensating capacitor through the remote control function; the method includes the following steps: Step 1: Determine the subordination relationship between the step-type reactive power compensator and the busbar; Step 2: Determine the busbar power switch; Step 3: Calculate the reactive power difference for adjusting the power switch; Step 4: Adjust the busbar voltage to keep it within the specified range; Step 5: Adjust the interest rate of the 220 kV substation to keep it within the specified range; In Step 1, the subordination relationship of each set of step-type reactive power compensators is the busbar where they are located, and the adjustment software can read it through the topological relationship of the substation background machine; the step-type reactive power compensator is only responsible for adjusting the reactive power and voltage of the busbar with a subordination relationship; the subordination relationship between the step-type reactive power compensator and the busbar is only related to the primary wiring and has nothing to do with the operation mode; In Step 2, after determining the subordinate busbar, it is necessary to determine the power switch of the busbar. According to different operation modes of the busbar, the power switch is also different. The operation modes of the busbar can be divided into three types: main transformer power supply operation, bus coupler switch power supply operation, and distribution network line series power supply operation; for the above three situations, the adjustment software first determines the positions of the main transformer switch and the bus coupler switch of the busbar to determine whether it is powered by this substation. If it is not powered by this substation, it is determined as distribution network line series power supply; Step 2 specifically includes the following steps: Step 2-1: Determine whether to read the bus coupler switch and the main transformer switch. If one of the positions is in the closed position, it is determined that the power supply is from this station; Step 2-2: If the main transformer switch is in the closed position and the bus coupler switch is in the open position, it is the main transformer power supply operation; in the main transformer power supply operation mode, it is necessary to calculate the qualification of the apparent power in a loop: the apparent power flowing through all main transformer switches is equal to the sum of the powers of other switches on the busbar. For a busbar, there is P 主变 +jQ 主变 = ∑P 其他 +jQ 其他 where P is the active power, Q is the reactive power, and j is the imaginary number in the apparent power calculation formula; When the verification is qualified, the result of the power switch is the main transformer switch; if the verification is unqualified, the regulation function of the busbar is blocked, and an alarm signal is issued. The program enters the switch position reading mode again; Step 2-3: If the main transformer switch is in the off position and the bus-tie switch is in the on position, it means the bus-tie switch is in the power supply operation mode. In the power supply operation mode of the bus-tie switch, it is necessary to calculate the qualification of the apparent power in a loop: the apparent power flowing through all bus-tie switches is equal to the sum of the powers of other switches on the busbar. For a busbar, there is P 母联 +jQ 母联 = ∑P 其他 +jQ 其他 When the verification is qualified, the result of the power switch is the bus-tie switch; if the verification is unqualified, the regulation function of the busbar is blocked, and an alarm signal is issued. The program enters the switch position reading mode again; Step 2-4: If the main transformer switch is in the on position and the bus-tie switch is in the on position, it is also the power supply operation mode of the bus-tie switch. In the power supply operation mode of the bus-tie switch, it is necessary to calculate the qualification of the apparent power in a loop: the apparent power flowing through all main transformer switches is equal to the sum of the powers of other switches on the busbar plus the apparent power flowing through the bus-tie switch. For a busbar, there is P 主变 +jQ 主变 =P 母联 +jQ 母联 +∑P 其他 +jQ 其他 When the verification is qualified, the result of the power switch is the main transformer switch minus the bus-tie switch; if the verification is unqualified, the regulation function of the busbar is blocked, and an alarm signal is issued. The program enters the switch position reading mode again; Step 2-5: If it is determined to be the power supply operation mode of the distribution network line series power supply, the program calculates the apparent power for each line with the switch in the on position; for each line n with the switch in the on position, calculate P Ln +jQ Ln = ∑P Li +jQ Li In the formula, L represents the line, and Li represents other lines on the busbar except line n; when the equation holds, line n is the power supply switch for the series power supply of the busbar, and the result is output; Step 2-6: For the locked situation, the above formula is calculated in a loop, and the lock is released when the calculation is qualified; at the same time, for the single-phase grounding abnormal situation, a real-time monitoring telemetry signal is set for automatic locking, and automatic unlocking is performed when the signal disappears.

2. An adaptive substation reactive power and voltage balance method according to claim 1, characterized in that, The substation background machine (5) sends the regulation capacity size to the SVG control cabinet (6) through the network switch.

3. An adaptive substation reactive power and voltage balance method according to claim 1, characterized in that, The substation background machine (5) sends the switch opening and closing command to the protection and measurement control device of the control switch (9) through the network switch to control the switching of capacitors.

4. An adaptive substation reactive power and voltage balance method according to claim 1, characterized in that, In step 3, for the power supply mode of this substation, before reactive power regulation, determine the allowable error value of reactive power; when the reactive power of the power switch is greater than the reactive power error value, perform a difference calculation and send an adjustment command to the stepped reactive power compensator to reduce the reactive power value of the power switch to 0; For the power supply operation mode of the distribution network line series power supply, in the special operation mode where the busbar is powered by the distribution network line series power supply, the relationship between the amount of capacitor input and the voltage change amount is uncertain. The adjustment of the capacity needs to be determined according to the busbar voltage situation. When the voltage is lower than the rated value, increase the capacitor input; when the voltage is higher than the rated value, reduce the capacitor input.

5. An adaptive reactive power and voltage balance method for a substation according to claim 1, characterized in that, in step 4, voltage regulation is only applicable to the power supply mode of this substation; after determining the allowable error value of reactive power, when the reactive power value of the power switch ≤ the allowable error value of reactive power after detection, if the bus voltage does not meet the voltage qualification requirements, the main transformer tap will participate in voltage regulation, and the tap will be upshifted or downshifted according to the actual situation to meet the voltage qualification requirements.

6. An adaptive reactive power and voltage balance method for a substation according to claim 1, characterized in that, to prevent the 220 kV bus rate from still not meeting the rate requirements after the reactive power and voltage balance regulation of this station and the lower-level substation, a stepped reactive power compensator is set on the low-voltage side of the 220 kV substation. On the premise of ensuring qualified voltage, all stepped reactive power compensators on this bus are only used to regulate the reactive power required for the rate; after the rate is unqualified, wait for 5 minutes to give the lower-level substation sufficient action time. If the rate requirements are still not met after 5 minutes, the regulation software reads the reactive power value required for calculating the overall station power factor in the substation background machine and inputs the corresponding reactive power to meet the rate requirements.

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